1. Field of the Invention
The present invention relates to a multi-way valve, a water purifier using the same, and to a method for distributing or mixing a fluid, and more particularly to a multi-way valve for distributing or mixing a fluid, and to a water purifier and a fluid distributing or mixing method that embodies this multi-way valve.
2. Description of the Prior Art
Conventional multi-way valves, for distributing or mixing a fluid, include a so-called rotary-type valve wherein individual fluid paths are switched by rotating a seal member (for example, U.S. Pat. Nos. 4,172,796, 4,770,768 and 5,160,038) and they also include a so-called sliding-type valve wherein fluid paths are switched by linearly moving a seal member. However, any of these multi-way valves has problems with durability and sealing. Therefore, in order to solve these problems, the following valves have been proposed.
(1) a multi-way valve wherein a plurality of spherical elements for closing fluid paths are provided in a valve casing having a single chamber, wherein any one spherical element is pressed and moved in a circumferential direction relative to the casing by rotating a rotatable shaft for opening a corresponding fluid path (for example, Japanese Utility Model Publication HEI-7-12770) PA0 (2) a multi-way valve wherein a fluid inlet and a plurality of fluid outlets are provided to a valve casing, and spherical elements are provided for closing the respective fluid outlets, and any spherical element is moved in a direction parallel to the axis of the rotatable member by rotating the rotatable member for opening a corresponding fluid outlet (for example, Japanese Utility Model Laid-Open HEI-4-132271) PA0 (3) a multi-way valve wherein a fluid inlet and two fluid outlets are provided in a valve casing, and balls are provided for closing the fluid outlets by pressure of water supplied from the fluid inlet, and any ball is displaced from a valve seat by rotation of a shift arm for opening a corresponding fluid outlet (for example, Japanese Utility Model Laid-Open HEI-6-16778)
However, when a multi-way valve described in the above (1) is employed, because the spherical element must be moved in a circumferential direction by rotating the rotatable shaft, the amount of movement of the spherical element inevitably becomes great, with the defect that the multi-way valve becomes large-sized and the amount of resident fluid in the valve increases causing a problem of poor hygienic property originating from the great amount of the resident fluid. Further, because the spherical elements must be taken off by disassembling the valve casing when the spherical elements are checked or exchanged for checking or improving the sealing ability due to the spherical elements, the required work becomes remarkably troublesome. Furthermore, there is a further problem that the shape of the rotatable shaft and the inside shape of the valve casing are complicated and the multi-way valve becomes expensive.
In a case where a multi-way valve described in case (2) is employed, because the spherical element must be moved in a direction parallel to the axis of the rotatable member by rotating the rotatable member, the amount of movement of the spherical element along the axis of the rotatable member becomes great, causing a defect that the multi-way valve becomes large-sized. If the multi-way valve becomes large-sized, the amount of resident fluid in the valve increases and there is a problem of poor hygienic property originating from the great amount of the resident fluid. Further, because the spherical elements must be taken off by disassembling the valve casing when the spherical elements are checked or exchanged for checking or improving the sealing ability due to the spherical elements, the work becomes considerably troublesome.
In a case where a multi-way valve described in the above (3) is employed, because the ball must be moved in a single chamber of the valve casing by rotating the shift arm, the size of the chamber inevitably becomes great, and the multi-way valve becomes large-sized, the amount of resident fluid in the valve increases and hygienic problems originate from the great amount of the resident fluid. Further, because the balls must be taken off by disassembling the valve casing when the balls are checked or exchanged for checking or improving the sealing ability due to the balls, the work becomes remarkably troublesome. Furthermore, because the shape and the attachment condition of the shift arm must be set in proper conditions, the multi-way valve must be assembled with meticulous care and there is a fear of causing a defect and the multi-way valve becomes expensive.
Further, a multi-way valve having an inflow path and a plurality of outflow paths wherein the fluid paths are switched by a pushing member is also known.
As this type of multi-way valve, as disclosed in Japanese Utility Model Publication SHO 63-8460 and Japanese Utility Model Laid-Open SHO 60-151972, there is a cylinder-piston type valve comprising a cylinder having a fluid inlet and fluid outlets and a piston sliding in the cylinder and having a seal member. Further, as disclosed as switching valves in JP-A-SHO 48-10631 and JP-A-SHO 52-45732, there is a ball-type valve closing a fluid outlet by a ball and opening the fluid outlet by moving the ball.
However, in the former cylinder-piston type multi-way valve, because the seal member fixed to the piston is slid on the fluid inlet or the fluid outlet of the cylinder while being pressed, there is a problem that abrasion quickly progresses and the seal member must be exchanged in a short period of time.
On the other hand, in the latter ball-type multi-way valve, because the fluid paths are switched by rolling the ball provided as a seal member, the problem of abrasion, such as the one in the former valve, can be improved. However, because an operating lever connected to an operating member provided for moving the ball extends through a valve box and both end portions thereof protrude outside of the valve box, a motion of grasping one end of the lever to pull the lever or pushing the other end of the lever is required for the switching operation, and such an operation is inconvenient and cannot be easily performed.
In order to improve such a problem, a valve able to operate only at one end of an operating lever was proposed, for example, as a ball-type water passage switching device for a faucet described in Japanese Utility Model Publication SHO 51-26357. In this switching device for a faucet, however, because a certain length is required for a rotatable shaft of an operating lever extending through a wall of a switching chamber in a direction perpendicular to the wall and a seal member must be provided for sealing the rotatable shaft, the valve body tends to become large-sized in the axial direction of the shaft and such a valve is not preferred as a valve for a faucet of an ordinary home. Further, because most faucets for an ordinary home are formed as a type in which a discharge pipe can be rotated in right-hand and left-hand directions (clockwise and counterclockwise directions), the method for operating an operating lever by moving the lever in right-hand and left-hand direction has a problem that the operation is not easy because the discharge pipe is rotated together with the operating lever.
Further, JP-B-HEI-5-31036 discloses a ball-type check valve for water in which an operating lever is moved in frontward and rearward directions relative to a discharge pipe. In this check valve, however, because pushing rods for moving balls, springs and seal members are required by the same number as that of fluid outlets, the number of parts increases and the structure of the valve becomes complicated.